The invention relates to an electron-beam heated vapor source assembly for use in the field of vaporizing materials in high vacuum and, especially the field of depositing multi-layer coatings on substrates.
Electron-beam heated vapor sources are frequently used in vacuum coating systems. One such vapor source is described in U.S. Pat. No. 3,710,072, issued to Robert L. Schrader and Kazumi N. Tsujimoto, and assigned to the assignee of the present application. This vapor source comprised a single crucible, a single electron-beam gun, and a magnetic means for deflecting the electron beam through an arcuate path from the electron-beam gun to the crucible. The magnetic deflecting means included two large, parallel plates of magnetic material which were positioned on opposite sides of the electron-beam gun and extended on opposite sides of the crucible. The plates were polarized by interconnecting them with a single permanent magnet near their ends which were further from the electron-beam gun. The electron beam was deflected by the magnetic field produced between the pole pieces. Three electro magnetic coils were arranged in a generally U-shaped structure to enable the beam to be swept across the crucible. This prior vapor source also included a pair of small plates, one bolted to the upper edge of each large pole plate. The small plate extended into the space between the large pole plates and enabled the production of a beam having a small cross section when it entered the crucible. The specification of this U.S. Pat. No. 3,710,072, is incorporated herein by reference.
U.S. Pat. No. 3,483,417 described another electron-beam heated vapor deposition source in which the beam was deflected by two large, parallel plates. This patent discloses interchangeable pole rods which are threaded into holes in the large plates. The threads enable adjustment of the distance which the pole rods extend into the space between the pole plates.
Electron-beam heated vapor sources having a plurality of crucibles for vaporizing different materials are also known. One such source is the model STIH-270-1 four-hearth source sold by the Temescal Division of the assignee of the present application. This source has a hearth assembly containing four separate compartments for material to be vaporized and a means for rotating the assembly about an axis so that each compartment may be placed into the path of the electron beam.